Ségolène Royal, who has been lying low since her presidential defeat against Nicolas Sarkozy seven months ago, is back in the limelight with a book - and a vengeance.

In Ma plus belle histoire, c'est vous (My Most Beautiful Story is You), a 330-page account of her campaign published in France yesterday, Royal blames the socialist party for her defeat, describes how she was spurned by her former partner and socialist party head, François Hollande, and makes it clear she will run again.

"I will win one day. I don't know where, and I don't know when, but I know we will find each other again," says Royal in her book. Writing in the third person, Royal adds that things will have to be different next time round: "The next candidate will need the full support of her party, and the full support of her partner - who must back the candidate completely."

In what reads like a justification rather than an analysis of what went wrong during her campaign, Royal says she "regrets nothing". Writing that her campaign wasn't as "slick" as her opponent's, she clearly blames the party's "elephants" - the long-serving leaders of the French socialist party - for letting her down: "I should have begged them, seduced them, stroked them the right way."

In one of the book's more notable passages, Royal reveals she had offered the post of prime minister to François Bayrou, the promising centrist candidate who lost in the first round. She describes calling him at midnight outside his flat before the second round. Bayrou begs her not to come up or leave the car "in case there are people in the street". He acted like "a lover who is worried he is not up to the task or shies away from a dangerous adultery", she writes.

Royal, who split from Hollande after the election, was criticised by many within her party and in the press for a lack of clear policies and "amateur" campaigning.

Unsurprisingly, the book, which follows a number of publications by socialist leaders following Royal's defeat, has not gone down well at party headquarters. Since the election the party has been split by infighting, made worse by the defection of some prominent socialist leaders to Sarkozy's government.

"Stop, stop, stop," Stéphane le Foll, an MEP and party member, told Libération. "We must stop blaming everything on the party's first secretary and saying it's the fault of the socialist party."

In a debate on Monday in Paris on the future of the socialist party Royal said it should become "a central force open to different strands from the far left, the centre and anti-globalists".

"This is just a beginning. The story goes on, by that I mean the fight," she writes in her book. "I am ready, optimistic and attached with all my being to the history of this country, and I will not allow it to stay in the state it is in today."